RS04 - Impact of 2023 Updated Intersocietal Accreditation Commission Interpretation Criteria for Carotid Stenosis on Thresholds for Treatment of Carotid Artery Disease

Objectives: In 2023, the Intersocietal Accreditation Commission (IAC) released recommendations to encourage standardization among laboratories for interpretation of carotid duplex ultrasound (CDU) based on peak systolic velocity (PSV) as the primary parameter. In this recommendation, the threshold for >70% stenosis was based on PSV >230 cm/sec as the primary parameter. Our study evaluated the potential impact of adopting the updated IAC interpretation criteria on the >70% threshold for carotid artery stenosis (CAS).

Methods: We performed a single-center retrospective study of patients who underwent CDU from July 2021-June 2023 at an IAC accredited outpatient vascular laboratory. PSV, end diastolic velocity (EDV) and ICA/common carotid artery (CCA) ratios were obtained from each ICA examined. The data was analyzed using PSV for >70% ICA stenosis, comparing the updated IAC criteria of >230 cm/sec to other thresholds. We then determined if the addition of EDV or ICA/CCA ratio impacted the change in classification based on PSV criteria.

Results: A total of 1219 patients were included with 3135 ICAs analyzed. Using published PSV ranges for ICA stenosis >70% between >150 cm/s and >360 cm/s, a total of 857 ICA stenoses fell within this range in our cohort. Using IAC criteria of PSV>230 cm/sec, a significant number of ICAs with a change in category would occur for labs with PSV thresholds >250 cm/s and < 210 cm/s (Table I). Using our validated vascular lab PSV threshold of 275 cm/s for 70% ICA stenosis, there was a 52% increase in those categorized as >70% (P <.0001) (Table II). Adding ICA/CCA ratio >4 to the PSV criteria, the difference was 26% and no longer statistically significant (P=.113). Adding EDV >100 to the PSV evaluation criteria, the increase was only 1.8% (P=.893). Finally, adding both EDV >100 and ICA/CCA ratio >4 to the PSV criteria, the increase was 1.1% increase (P=.940).

Conclusions: This study demonstrated the difference in ICA stenosis interpretation when using PSV as the primary parameter as the updated IAC guidelines suggest. This represented a significant number of patients who would change categorization from < 70% stenosis to >70% stenosis, potentially leading to significant differences in patient management. However, inclusion of EDV and/or ICA/CCA ratio mitigated any statistically significant difference in categorization.